My truck is a long bed 1998 K1500 with a 305 and auto trans. Mileage is 153,000.

For the last several months I have had the Service Engine Soon light coming on at random intervals. The light will stay on for a few days and will then go off. It seems to be coming on at more frequent intervals lately. Other than the light coming on, the truck runs like a top and starts easily in any conditions.

The code is;
P0401 -- Exhaust Gas Recirculation Flow Insufficient Detected

I have replaced the EGR valve, cleaned the PCV valve, changed plugs, plug wires, distributor cap & rotor, and changed the fuel and air filter.
None of these have made any difference. I have been told that the MAP sensor and/or the MAF (Mass Air Flow) sensor could also cause this code.

I have managed to locate the MAF sensor but for the life of me I cannot find the MAP sensor. Can anyone tell me where it is located on my truck? I have a Haynes manual on order but it hasn't arrived yet.


Thanks for any help,
Larry

 

The MAP sensor is located on the upper intake manifold plenum. Before taking it out, i would just check and make sure its not just a loose wire because playing with it might keep the check engine light on and you have to get it reset.